From nobody Tue Apr 7 19:54:17 2026 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 5747B364EB0; Fri, 27 Feb 2026 17:56:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772214987; cv=none; b=SCvD0vXJvEGBWMgm0LB0q9aZBPafj3BbhOgL/b9UwRo95PmbnLuViLogVm33CeVADueASsJCzqsbACdGiX5IWQcRBAx9xJHRZst6IZbwoPxPkR6eN/BErUw82naX5QRbw/Gu0MBXzH1z94B48NS6P+WqbzvPo0ckint50DsA+0Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772214987; c=relaxed/simple; bh=CVECHLTJTrkj0HSvNoMBBYYeRNbXtXG21b2MTJVwoyU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BZQ6PK/qSGS2OgMG0typgW0vjIVCkMkF8HPWo1syDtU4x9FS3Y8ztmKsvIQvTYVOhnzOqP4akHTnoFUcXCqvT6qTAu8V7QB2OWraPG6FGj7WgQQJT3VasHZ8MajGpBeqDVn0N6yKXS7FGZJgPV5nRZRY9RMN0Mu3/HPxBX3Tz5E= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 783D814BF; Fri, 27 Feb 2026 09:56:19 -0800 (PST) Received: from e123572-lin.arm.com (e123572-lin.cambridge.arm.com [10.1.194.54]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5F0893F73B; Fri, 27 Feb 2026 09:56:21 -0800 (PST) From: Kevin Brodsky To: linux-hardening@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Kevin Brodsky , Andrew Morton , Andy Lutomirski , Catalin Marinas , Dave Hansen , David Hildenbrand , Ira Weiny , Jann Horn , Jeff Xu , Joey Gouly , Kees Cook , Linus Walleij , Lorenzo Stoakes , Marc Zyngier , Mark Brown , Matthew Wilcox , Maxwell Bland , "Mike Rapoport (IBM)" , Peter Zijlstra , Pierre Langlois , Quentin Perret , Rick Edgecombe , Ryan Roberts , Thomas Gleixner , Vlastimil Babka , Will Deacon , Yang Shi , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org Subject: [PATCH v6 09/30] arm64: Initialize POR_EL1 register on cpu_resume() Date: Fri, 27 Feb 2026 17:54:57 +0000 Message-ID: <20260227175518.3728055-10-kevin.brodsky@arm.com> X-Mailer: git-send-email 2.51.2 In-Reply-To: <20260227175518.3728055-1-kevin.brodsky@arm.com> References: <20260227175518.3728055-1-kevin.brodsky@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Yeoreum Yun The POR_EL1 register is reset to an unknown value after cpu_suspend(). Since POR_EL1 always holds POR_EL1_INIT when entering cpu_suspend(), initialize POR_EL1 with POR_EL1_INIT before cpu_do_resume(). Signed-off-by: Yeoreum Yun Signed-off-by: Kevin Brodsky --- arch/arm64/kernel/sleep.S | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S index f093cdf71be1..e0a6ad85cd24 100644 --- a/arch/arm64/kernel/sleep.S +++ b/arch/arm64/kernel/sleep.S @@ -3,6 +3,7 @@ #include #include #include +#include #include =20 .text @@ -134,6 +135,17 @@ SYM_FUNC_START(_cpu_resume) /* load sp from context */ ldr x2, [x0, #CPU_CTX_SP] mov sp, x2 + +#ifdef CONFIG_ARM64_POE +alternative_if_not ARM64_HAS_S1POE + b .Lskip_por_set +alternative_else_nop_endif + mov_q x2, POR_EL1_INIT + msr_s SYS_POR_EL1, x2 + /* isb can be skipped since cpu_do_resume() will do it. */ +.Lskip_por_set: +#endif /* CONFIG_ARM64_POE */ + /* * cpu_do_resume expects x0 to contain context address pointer */ --=20 2.51.2